Container base



FIG. 1 is a top perspective view of the container base;

FIG. 2 is a bottom perspective view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a front elevation view thereof;

FIG. 6 is a rear elevation view thereof;

FIG. 7 is a left side elevation view thereof; and,

FIG. 8 is a right side elevation view thereof. 

CLAIM The ornamental design for a container base, as shown and described. 